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5e27d79314
sysentvec. This allows the timekeep data to be shared between similar ABIs which cannot share sysentvec. Make the timekeep_push_vdso() tick callback to the timekeep structures instead of sysentvecs. If several sysentvec share the vdso_sv_tk structure, we would update the userspace data several times on each tick, without the change. Only allocate vdso_sv_tk in the exec_sysvec_init() sysinit when sysentvec is marked with the new SV_TIMEKEEP flag. This saves allocation and update of unneeded vdso_sv_tk for ABIs which do not provide userspace gettimeofday yet, which are PowerPCs arches right now. Make vdso_sv_tk allocator public, namely split out and export alloc_sv_tk() and alloc_sv_tk_compat32(). ABIs which share timekeep data now can allocate it manually and share as appropriate. Requested by: nwhitehorn Tested by: nwhitehorn, pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
289 lines
7.6 KiB
C
289 lines
7.6 KiB
C
/*-
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* Copyright (c) 2010, 2012 Konstantin Belousov <kib@FreeBSD.org>
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* Copyright (c) 2015 The FreeBSD Foundation
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_compat.h"
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#include "opt_vm.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/rwlock.h>
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#include <sys/sysent.h>
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#include <sys/sysctl.h>
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#include <sys/vdso.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_extern.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_map.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pager.h>
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static struct sx shared_page_alloc_sx;
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static vm_object_t shared_page_obj;
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static int shared_page_free;
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char *shared_page_mapping;
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void
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shared_page_write(int base, int size, const void *data)
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{
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bcopy(data, shared_page_mapping + base, size);
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}
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static int
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shared_page_alloc_locked(int size, int align)
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{
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int res;
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res = roundup(shared_page_free, align);
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if (res + size >= IDX_TO_OFF(shared_page_obj->size))
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res = -1;
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else
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shared_page_free = res + size;
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return (res);
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}
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int
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shared_page_alloc(int size, int align)
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{
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int res;
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sx_xlock(&shared_page_alloc_sx);
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res = shared_page_alloc_locked(size, align);
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sx_xunlock(&shared_page_alloc_sx);
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return (res);
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}
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int
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shared_page_fill(int size, int align, const void *data)
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{
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int res;
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sx_xlock(&shared_page_alloc_sx);
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res = shared_page_alloc_locked(size, align);
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if (res != -1)
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shared_page_write(res, size, data);
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sx_xunlock(&shared_page_alloc_sx);
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return (res);
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}
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static void
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shared_page_init(void *dummy __unused)
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{
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vm_page_t m;
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vm_offset_t addr;
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sx_init(&shared_page_alloc_sx, "shpsx");
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shared_page_obj = vm_pager_allocate(OBJT_PHYS, 0, PAGE_SIZE,
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VM_PROT_DEFAULT, 0, NULL);
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VM_OBJECT_WLOCK(shared_page_obj);
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m = vm_page_grab(shared_page_obj, 0, VM_ALLOC_NOBUSY | VM_ALLOC_ZERO);
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m->valid = VM_PAGE_BITS_ALL;
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VM_OBJECT_WUNLOCK(shared_page_obj);
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addr = kva_alloc(PAGE_SIZE);
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pmap_qenter(addr, &m, 1);
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shared_page_mapping = (char *)addr;
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}
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SYSINIT(shp, SI_SUB_EXEC, SI_ORDER_FIRST, (sysinit_cfunc_t)shared_page_init,
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NULL);
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/*
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* Push the timehands update to the shared page.
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*
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* The lockless update scheme is similar to the one used to update the
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* in-kernel timehands, see sys/kern/kern_tc.c:tc_windup() (which
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* calls us after the timehands are updated).
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*/
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static void
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timehands_update(struct vdso_sv_tk *svtk)
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{
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struct vdso_timehands th;
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struct vdso_timekeep *tk;
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uint32_t enabled, idx;
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enabled = tc_fill_vdso_timehands(&th);
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th.th_gen = 0;
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idx = svtk->sv_timekeep_curr;
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if (++idx >= VDSO_TH_NUM)
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idx = 0;
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svtk->sv_timekeep_curr = idx;
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if (++svtk->sv_timekeep_gen == 0)
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svtk->sv_timekeep_gen = 1;
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tk = (struct vdso_timekeep *)(shared_page_mapping +
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svtk->sv_timekeep_off);
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tk->tk_th[idx].th_gen = 0;
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atomic_thread_fence_rel();
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if (enabled)
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tk->tk_th[idx] = th;
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atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
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atomic_store_rel_32(&tk->tk_current, idx);
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/*
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* The ordering of the assignment to tk_enabled relative to
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* the update of the vdso_timehands is not important.
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*/
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tk->tk_enabled = enabled;
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}
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#ifdef COMPAT_FREEBSD32
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static void
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timehands_update32(struct vdso_sv_tk *svtk)
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{
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struct vdso_timehands32 th;
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struct vdso_timekeep32 *tk;
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uint32_t enabled, idx;
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enabled = tc_fill_vdso_timehands32(&th);
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th.th_gen = 0;
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idx = svtk->sv_timekeep_curr;
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if (++idx >= VDSO_TH_NUM)
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idx = 0;
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svtk->sv_timekeep_curr = idx;
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if (++svtk->sv_timekeep_gen == 0)
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svtk->sv_timekeep_gen = 1;
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tk = (struct vdso_timekeep32 *)(shared_page_mapping +
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svtk->sv_timekeep_off);
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tk->tk_th[idx].th_gen = 0;
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atomic_thread_fence_rel();
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if (enabled)
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tk->tk_th[idx] = th;
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atomic_store_rel_32(&tk->tk_th[idx].th_gen, svtk->sv_timekeep_gen);
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atomic_store_rel_32(&tk->tk_current, idx);
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tk->tk_enabled = enabled;
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}
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#endif
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/*
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* This is hackish, but easiest way to avoid creating list structures
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* that needs to be iterated over from the hardclock interrupt
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* context.
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*/
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static struct vdso_sv_tk *host_svtk;
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#ifdef COMPAT_FREEBSD32
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static struct vdso_sv_tk *compat32_svtk;
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#endif
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void
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timekeep_push_vdso(void)
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{
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if (host_svtk != NULL)
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timehands_update(host_svtk);
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#ifdef COMPAT_FREEBSD32
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if (compat32_svtk != NULL)
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timehands_update32(compat32_svtk);
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#endif
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}
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struct vdso_sv_tk *
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alloc_sv_tk(void)
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{
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struct vdso_sv_tk *svtk;
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int tk_base;
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uint32_t tk_ver;
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tk_ver = VDSO_TK_VER_CURR;
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svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
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tk_base = shared_page_alloc(sizeof(struct vdso_timekeep) +
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sizeof(struct vdso_timehands) * VDSO_TH_NUM, 16);
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KASSERT(tk_base != -1, ("tk_base -1 for native"));
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shared_page_write(tk_base + offsetof(struct vdso_timekeep, tk_ver),
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sizeof(uint32_t), &tk_ver);
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svtk->sv_timekeep_off = tk_base;
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timekeep_push_vdso();
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return (svtk);
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}
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#ifdef COMPAT_FREEBSD32
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struct vdso_sv_tk *
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alloc_sv_tk_compat32(void)
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{
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struct vdso_sv_tk *svtk;
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int tk_base;
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uint32_t tk_ver;
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svtk = malloc(sizeof(struct vdso_sv_tk), M_TEMP, M_WAITOK | M_ZERO);
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tk_ver = VDSO_TK_VER_CURR;
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tk_base = shared_page_alloc(sizeof(struct vdso_timekeep32) +
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sizeof(struct vdso_timehands32) * VDSO_TH_NUM, 16);
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KASSERT(tk_base != -1, ("tk_base -1 for 32bit"));
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shared_page_write(tk_base + offsetof(struct vdso_timekeep32,
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tk_ver), sizeof(uint32_t), &tk_ver);
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svtk->sv_timekeep_off = tk_base;
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timekeep_push_vdso();
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return (svtk);
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}
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#endif
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void
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exec_sysvec_init(void *param)
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{
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struct sysentvec *sv;
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sv = (struct sysentvec *)param;
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if ((sv->sv_flags & SV_SHP) == 0)
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return;
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sv->sv_shared_page_obj = shared_page_obj;
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sv->sv_sigcode_base = sv->sv_shared_page_base +
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shared_page_fill(*(sv->sv_szsigcode), 16, sv->sv_sigcode);
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if ((sv->sv_flags & SV_ABI_MASK) != SV_ABI_FREEBSD)
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return;
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if ((sv->sv_flags & SV_TIMEKEEP) != 0) {
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#ifdef COMPAT_FREEBSD32
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if ((sv->sv_flags & SV_ILP32) != 0) {
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KASSERT(compat32_svtk == NULL,
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("Compat32 already registered"));
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compat32_svtk = alloc_sv_tk_compat32();
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sv->sv_timekeep_base = sv->sv_shared_page_base +
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compat32_svtk->sv_timekeep_off;
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} else {
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#endif
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KASSERT(host_svtk == NULL, ("Host already registered"));
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host_svtk = alloc_sv_tk();
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sv->sv_timekeep_base = sv->sv_shared_page_base +
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host_svtk->sv_timekeep_off;
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#ifdef COMPAT_FREEBSD32
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}
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#endif
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}
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}
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